1. Field of the Invention
The present invention relates to a process for polymerizing an aromatic vinyl compound, and a catalyst therefore. More particularly, the present invention relates to a process for producing a polymer of an aromatic vinyl compound, mainly in a syndiotactic configuration with high selectivity, and a catalyst therefore.
2. Description of the Background
Aromatic vinyl polymers are classified into three types according to the steric configuration thereof: namely, syndiotactic polymers, isotactic polymers, and atactic polymers. Of these three types of polymers, the syndiotactic polymers are useful as heat-resistant polymers owing to their higher melting points and lower crystallization rates in comparison with other types of polymers. The syndiotactic aromatic vinyl polymers are produced, for example, with a catalyst formed by contact of a titanium compound, such as a titanium halide and an alkoxy titanium, with an organic aluminum compound and a condensing agent as described in Japanese Laid-Open Patent Application Sho 62-104818.
Conventional processes, such as are represented by Japanese patent application Hei 2-53711, have the disadvantage that the formed syndiotactic aromatic vinyl polymer inevitably contains an atactic polymer as a by-product.
Thus, a need exists for a process by which a syndiotactic aromatic vinyl polymer can be produced with a high degree of selectivity.